GW Pharmaceuticals announced on Monday that their experimental cannabis-based drug, Epidiolex, was able to reduce epileptic seizure in its first major test. The result may support the medical marijuana movement.

The Epilodex has achieved its goal to reduce convulsive seizures on the trial where it has been compared to a placebo taken by the patients with Dravet syndrome, which is a rare form of epilepsy. The result also increased GW shares on Monday, according to New York Times.

Epilodex will be the first prescription drug in the United States that is marijuana-based if it wins the regulatory approval. It contains cannabidiol, the herb's component that does not make people high.

Some parents are turning to marijuana extracts from medical marijuana dispensaries. This is because around 30 percent of around 500,000 children with epilepsy does not benefit from existing drugs.

Some states have passed or are considering legislations making the marijuana-based products easier to obtain to address the pressure from these parents. Some families moved to Colorado where they can easily get a specific extract called the Charlotte's Web, it was named after the first girl who used it to control her seizures.

Meanwhile, Epilodex is now on its Phase III trial for another rare type of epilepsy, the Lennox-Gastaut syndrome. Its results are expected this year. There will also be a late-stage study in a third epilepsy indication and a study regarding tuberous sclerosis complex will start soon, as reported by Reuters.

On an average, analysts believe that the drug could generate $1.1 billion of annual sales by 2021, based on a consensus forecast compiled by Thomson Reuters Cortellis.

On the other hand, GW Pharmaceuticals was founded in 1998, aiming to capitalize on medical marijuana. It has manufactured Sativex, a multiple sclerosis treatment which is sprayed under the tongue. It has been approved in more than 20 countries but not in the United States.